Regression of a thrombosed persistent sciatic artery aneurysm

A 79-year-old woman who had a previous history of sudden onset of pain and coldness of her right leg was referred to our hospital. There were no palpable right popliteal and pedal pulses with the ankle-brachial pressure index being 0.63. Computed tomography showed a 2.6-cm diameter right buttock mass which had a continuation from the right internal iliac artery that entered the posterior thigh and continued to the popliteal artery. It was diagnosed as thrombosed right persistent sciatic artery (PSA) aneurysm. She was treated medically with intravenous and oral antiplatelets, and was left with no right leg symptoms. Follow-up CT obtained after 3 years from onset demonstrated that the diameter of the PSA aneurysm diminished from 2.6 to 1.2 cm. It is suggested that a patient who had the occluded complete type PSA aneurysm with no critical leg ischemia, local compression, or rupture can be observed without surgery. However, careful follow-up of the patient is essential.